@benjie I've searched for the YouTube videos you mention and can't find them. Could you provide a link, please? I am inclined to agree with lewm, though, that antiskating with the ET-2 is covered by having the turntable perfectly level.
FWIW, I did increase the VTF of my Ruby 2 to the max. recommended VTF of 2.2. I didn't hear any significant difference in going from 2 g to 2.2 g.
When I've got nothing better to do, I may pull out my old Thorens with its Grace F9E cartridge and see how it tracks the Larajii LP. I made the cassette dub of this with the Talisman Alchemist IIb cartridge that the dealer originally installed on the ET-2 when I bought the turntable; the distortion isn't present on that recording, and my Nak cassette deck made very faithful recordings that would have shown such distortion if it were present.
The only things different in my setup now (other than the cartridge change) is that I added a very thin felt mat to my SOTA and a damping trough to the ET-2. The latter was an addition recommended and made by Eminent Technology (Bruce Thigpen); it is filled with a silicon fluid provided with the trough. The manual claimed it had reduced flutter on one turntable down to .007%, and that their tests showed that wow and flutter is a product of the tonearm, not just the turntable. It says linear-tracking tonearms have lower wow and flutter than pivoted arms--one more reason to go with LT arms!